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ring-buffer: Avoid softlockup in ring_buffer_resize()

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[ Upstream commit f6bd2c92488c30ef53b5bd80c52f0a7eee9d545a ]

When user resize all trace ring buffer through file 'buffer_size_kb',
then in ring_buffer_resize(), kernel allocates buffer pages for each
cpu in a loop.

If the kernel preemption model is PREEMPT_NONE and there are many cpus
and there are many buffer pages to be allocated, it may not give up cpu
for a long time and finally cause a softlockup.

To avoid it, call cond_resched() after each cpu buffer allocation.

Link: https://lore.kernel.org/linux-trace-kernel/20230906081930.3939106-1-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Zheng Yejian 2023-09-06 16:19:30 +08:00 committed by Greg Kroah-Hartman
parent 1d28224d49
commit 05264d6551
1 changed files with 2 additions and 0 deletions
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2
kernel/trace/ring_buffer.c
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@ -1821,6 +1821,8 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size,
err = -ENOMEM; err = -ENOMEM;
goto out_err; goto out_err;
} }
cond_resched();
} }
get_online_cpus(); get_online_cpus();